A stack which works with or without an Mbed os library. Provides IPv4 or IPv6 with a full 1500 byte buffer.
Dependents: oldheating gps motorhome heating
udp/dns/dnslabel.c
- Committer:
- andrewboyson
- Date:
- 2019-03-11
- Revision:
- 128:79052cb4a41c
- Child:
- 182:ff48c6ea91c1
File content as of revision 128:79052cb4a41c:
#include <stdbool.h> #include <string.h> #include "dns.h" #include "dnslabel.h" #include "dhcp.h" void DnsLabelCopy(char* dst, char* src) { strncpy(dst, src, DNS_MAX_LABEL_LENGTH); //Copies up to 63 bytes dst[DNS_MAX_LABEL_LENGTH] = 0; //dst[63] is the 64th position from 0..63 is set to null. All labels must be declared as a size of 64 } bool DnsLabelIsSame(char* pA, char* pB) { while(true) { char a = *pA++; char b = *pB++; if (a >= 'A' && a <= 'Z') a |= 0x20; //Make lower case if (b >= 'A' && b <= 'Z') b |= 0x20; //Make lower case if (a != b) return false; //If different then stop and return the fact if (!a) break; //No need to check 'b' too as it will necessarily be equal to 'a' at this point. } return true; //If we get here the strings must equate. } int DnsLabelMakeFullNameFromName(int protocol, const char* p, int size, char* result) { int i = 0; char c; while (i < size - 1) { c = *p++; if (!c) break; *result++ = c; i++; } if (protocol == DNS_PROTOCOL_MDNS) { p = ".local"; while (i < size - 1) { c = *p++; if (!c) break; *result++ = c; i++; } } if (protocol == DNS_PROTOCOL_UDNS && DhcpDomainName[0]) //Shouldn't do this in IPv6 as DHCP is IPv4 only { if (i < size - 1) { *result++ = '.'; i++; } p = DhcpDomainName; while (i < size - 1) { c = *p++; if (!c) break; *result++ = c; i++; } } *result = 0; //Terminate the resulting string return i; } int DnsLabelStripNameFromFullName(int protocol, char* p, int size, char* result) { int i = 0; char c; while (i < size - 1) { c = *p++; if (c == 0) break; //End of the fqdn so stop if (c == '.') { if (protocol == DNS_PROTOCOL_UDNS) { if (strcmp(p, DhcpDomainName) == 0) break; //Strip the domain from a UDNS fqdn if, and only if, it matches the domain given in DHCP. IPv4 only. } else { break; //Strip the domain from an LLMNR (there shouldn't be one) or MDNS (it should always be '.local') fqdn } } *result++ = c; i++; } *result = 0; //Terminate the copied string return i; }